    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *     http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.configuration2.io;
    018
    019import java.net.URL;
    020
    021import org.apache.commons.lang3.StringUtils;
    022import org.apache.commons.lang3.builder.EqualsBuilder;
    023import org.apache.commons.lang3.builder.HashCodeBuilder;
    024import org.apache.commons.lang3.builder.ToStringBuilder;
    025
    026/**
    027 * <p>
    028 * A class describing the location of a file.
    029 * </p>
    030 * <p>
    031 * An instance of this class provides information for locating and accessing a
    032 * file. The file location can be defined
    033 * </p>
    034 * <ul>
    035 * <li>as a URL; this identifies a file in a unique way</li>
    036 * <li>as a combination of base path and file name; if this variant is used,
    037 * there may be an additional location step required in order to identify the
    038 * referenced file (for instance, the file name may be interpreted as the name
    039 * of a resource to be loaded from class path).</li>
    040 * </ul>
    041 * <p>
    042 * In addition, other properties are available which are also needed for loading
    043 * or saving a file, like the underlying {@link FileSystem}. The encoding to be
    044 * used when accessing the represented data is also part of the data contained
    045 * in an instance; if no encoding is set explicitly, the platform's default
    046 * encoding is used.
    047 * <p>
    048 * Instances of this class are immutable and thus can be safely shared between
    049 * arbitrary components. {@link FileHandler} also uses an instance to reference
    050 * the associated file. Instances are created using a <em>builder</em>.
    051 * {@link FileLocatorUtils} offers convenience methods for obtaining such a
    052 * builder.
    053 * </p>
    054 *
    055 * @version $Id: FileLocator.java 1842194 2018-09-27 22:24:23Z ggregory $
    056 * @since 2.0
    057 */
    058public final class FileLocator
    059{
    060    /** The file name. */
    061    private final String fileName;
    062
    063    /** The base path. */
    064    private final String basePath;
    065
    066    /** The source URL. */
    067    private final URL sourceURL;
    068
    069    /** The encoding. */
    070    private final String encoding;
    071
    072    /** The file system. */
    073    private final FileSystem fileSystem;
    074
    075    /** The file location strategy. */
    076    private final FileLocationStrategy locationStrategy;
    077
    078    /**
    079     * Creates a new instance of {@code FileLocatorImpl} and initializes it from
    080     * the given builder instance
    081     *
    082     * @param builder the builder
    083     */
    084    public FileLocator(final FileLocatorBuilder builder)
    085    {
    086        fileName = builder.fileName;
    087        basePath = builder.basePath;
    088        sourceURL = builder.sourceURL;
    089        encoding = builder.encoding;
    090        fileSystem = builder.fileSystem;
    091        locationStrategy = builder.locationStrategy;
    092    }
    093
    094    /**
    095     * Returns the file name stored in this locator or <b>null</b> if it is
    096     * undefined.
    097     *
    098     * @return the file name
    099     */
    100    public String getFileName()
    101    {
    102        return fileName;
    103    }
    104
    105    /**
    106     * Returns the base path stored in this locator or <b>null</b> if it is
    107     * undefined.
    108     *
    109     * @return the base path
    110     */
    111    public String getBasePath()
    112    {
    113        return basePath;
    114    }
    115
    116    /**
    117     * Returns the URL pointing to the referenced source file or <b>null</b> if
    118     * it is undefined.
    119     *
    120     * @return the source URL
    121     */
    122    public URL getSourceURL()
    123    {
    124        return sourceURL;
    125    }
    126
    127    /**
    128     * Returns the encoding stored in this locator or <b>null</b> if it is
    129     * undefined.
    130     *
    131     * @return the encoding
    132     */
    133    public String getEncoding()
    134    {
    135        return encoding;
    136    }
    137
    138    /**
    139     * Returns the {@code FileSystem} to be used for accessing the file
    140     * referenced by this locator or <b>null</b> if it is undefined.
    141     *
    142     * @return the {@code FileSystem}
    143     */
    144    public FileSystem getFileSystem()
    145    {
    146        return fileSystem;
    147    }
    148
    149    /**
    150     * Returns the {@code FileLocationStrategy} to be used for locating the
    151     * referenced file. If no specific {@code FileLocationStrategy} has been
    152     * set, result is <b>null</b>. This means that the default strategy should
    153     * be used.
    154     *
    155     * @return the {@code FileLocationStrategy} to be used
    156     */
    157    public FileLocationStrategy getLocationStrategy()
    158    {
    159        return locationStrategy;
    160    }
    161
    162    /**
    163     * Returns a hash code for this object.
    164     *
    165     * @return a hash code for this object
    166     */
    167    @Override
    168    public int hashCode()
    169    {
    170        return new HashCodeBuilder().append(getFileName())
    171                .append(getBasePath()).append(sourceURLAsString())
    172                .append(getEncoding()).append(getFileSystem())
    173                .append(getLocationStrategy()).toHashCode();
    174    }
    175
    176    /**
    177     * Compares this object with another one. Two instances of
    178     * {@code FileLocatorImpl} are considered equal if all of their properties
    179     * are equal.
    180     *
    181     * @param obj the object to compare to
    182     * @return a flag whether these objects are equal
    183     */
    184    @Override
    185    public boolean equals(final Object obj)
    186    {
    187        if (this == obj)
    188        {
    189            return true;
    190        }
    191        if (!(obj instanceof FileLocator))
    192        {
    193            return false;
    194        }
    195
    196        final FileLocator c = (FileLocator) obj;
    197        return new EqualsBuilder().append(getFileName(), c.getFileName())
    198                .append(getBasePath(), c.getBasePath())
    199                .append(sourceURLAsString(), c.sourceURLAsString())
    200                .append(getEncoding(), c.getEncoding())
    201                .append(getFileSystem(), c.getFileSystem())
    202                .append(getLocationStrategy(), c.getLocationStrategy())
    203                .isEquals();
    204    }
    205
    206    /**
    207     * Returns a string representation of this object. This string contains the
    208     * values of all properties.
    209     *
    210     * @return a string for this object
    211     */
    212    @Override
    213    public String toString()
    214    {
    215        return new ToStringBuilder(this).append("fileName", getFileName())
    216                .append("basePath", getBasePath())
    217                .append("sourceURL", sourceURLAsString())
    218                .append("encoding", getEncoding())
    219                .append("fileSystem", getFileSystem())
    220                .append("locationStrategy", getLocationStrategy()).toString();
    221    }
    222
    223    /**
    224     * Returns the source URL as a string. Result is never null. Comparisons are
    225     * done on this string to avoid blocking network calls.
    226     *
    227     * @return the source URL as a string (not null)
    228     */
    229    private String sourceURLAsString()
    230    {
    231        return (sourceURL != null) ? sourceURL.toExternalForm()
    232                : StringUtils.EMPTY;
    233    }
    234
    235    /**
    236     * A typical <em>builder</em> implementation for creating
    237     * {@code FileLocator} objects. An instance of this class is returned by the
    238     * {@code fileLocator()} method of {link FileLocatorUtils}. It can be used
    239     * to define the various components of the {@code FileLocator} object. By
    240     * calling {@code create()} the new immutable {@code FileLocator} instance
    241     * is created.
    242     */
    243    public static final class FileLocatorBuilder
    244    {
    245        /** The file name. */
    246        private String fileName;
    247
    248        /** The base path. */
    249        private String basePath;
    250
    251        /** The source URL. */
    252        private URL sourceURL;
    253
    254        /** The encoding. */
    255        private String encoding;
    256
    257        /** The file system. */
    258        private FileSystem fileSystem;
    259
    260        /** The location strategy. */
    261        private FileLocationStrategy locationStrategy;
    262
    263        /**
    264         * Creates a new instance of {@code FileLocatorBuilder} and initializes
    265         * the builder's properties from the passed in {@code FileLocator}
    266         * object.
    267         *
    268         * @param src the source {@code FileLocator} (may be <b>null</b>)
    269         */
    270        FileLocatorBuilder(final FileLocator src)
    271        {
    272            if (src != null)
    273            {
    274                initBuilder(src);
    275            }
    276        }
    277
    278        /**
    279         * Specifies the encoding of the new {@code FileLocator}.
    280         *
    281         * @param enc the encoding
    282         * @return a reference to this builder for method chaining
    283         */
    284        public FileLocatorBuilder encoding(final String enc)
    285        {
    286            encoding = enc;
    287            return this;
    288        }
    289
    290        /**
    291         * Specifies the {@code FileSystem} of the new {@code FileLocator}.
    292         *
    293         * @param fs the {@code FileSystem}
    294         * @return a reference to this builder for method chaining
    295         */
    296        public FileLocatorBuilder fileSystem(final FileSystem fs)
    297        {
    298            fileSystem = fs;
    299            return this;
    300        }
    301
    302        /**
    303         * Specifies the base path of the new {@code FileLocator}.
    304         *
    305         * @param path the base path
    306         * @return a reference to this builder for method chaining
    307         */
    308        public FileLocatorBuilder basePath(final String path)
    309        {
    310            basePath = path;
    311            return this;
    312        }
    313
    314        /**
    315         * Specifies the file name of the new {@code FileLocator}.
    316         *
    317         * @param name the file name
    318         * @return a reference to this builder for method chaining
    319         */
    320        public FileLocatorBuilder fileName(final String name)
    321        {
    322            fileName = name;
    323            return this;
    324        }
    325
    326        /**
    327         * Specifies the source URL of the new {@code FileLocator}.
    328         *
    329         * @param url the source URL
    330         * @return a reference to this builder for method chaining
    331         */
    332        public FileLocatorBuilder sourceURL(final URL url)
    333        {
    334            sourceURL = url;
    335            return this;
    336        }
    337
    338        /**
    339         * Specifies the {@code FileLocationStrategy} to be used when the
    340         * referenced file is to be located.
    341         *
    342         * @param strategy the {@code FileLocationStrategy}
    343         * @return a reference to this builder for method chaining
    344         */
    345        public FileLocatorBuilder locationStrategy(final FileLocationStrategy strategy)
    346        {
    347            locationStrategy = strategy;
    348            return this;
    349        }
    350
    351        /**
    352         * Creates a new immutable {@code FileLocatorImpl} object based on the
    353         * properties set so far for this builder.
    354         *
    355         * @return the newly created {@code FileLocator} object
    356         */
    357        public FileLocator create()
    358        {
    359            return new FileLocator(this);
    360        }
    361
    362        /**
    363         * Initializes the properties of this builder from the passed in locator
    364         * object.
    365         *
    366         * @param src the source {@code FileLocator}
    367         */
    368        private void initBuilder(final FileLocator src)
    369        {
    370            basePath = src.getBasePath();
    371            fileName = src.getFileName();
    372            sourceURL = src.getSourceURL();
    373            encoding = src.getEncoding();
    374            fileSystem = src.getFileSystem();
    375            locationStrategy = src.getLocationStrategy();
    376        }
    377    }
    378}